Cutting tool for forming shaped articles

ABSTRACT

A cutting tool for forming articles which acquire in the process of machining the negative shape of said tool. The tool consists of a holder and a shaped cutting element made of a compound based on polymers and cutting particles and fastened to said holder by a joint which is capable of withstanding the load imposed by the forces of cutting and of being easily destroyed during the replacement of the cutting element.

United States Patent 1 1 Fedjukin et al.

[ CUTTING TOOL FOR FORMING SHAPED ARTICLES [76] inventors: DmitryLvovich Fedjukin,

, Novogireevskaya ulitsa, 4, kv. 106;

Ljudmila Semenovna Sergeeva, Lenisky prospekt, 97 b, korpus 107, Irv.59; Andrei Nllrolaevich Bairhnrev, 3 Cherkizovskaya ulitsa, 78, kv. 2;Petr Evmenovich Korochkin, N. Pervomaiskaya ulitsa, 66, kv. 32; AnatolyIzrailevlch Aronov, ulitsa Vavilova, 70, korpus 3, kv. 237; InnaLeonldovna Gorlina, ulitsa Panfilova, 4/5, korpus l6, kv. 79; Arkady.Tlmofeevich Kravets, ulitsa Vavilova, 70 korpus 3, kv. 198, all ofMoscow; Emmanuil lsaakovich Goloskov, ulitsa 7, kv. l7, Leningrad;Ernest Alexandrovlch Annenberg, ulitsa Shukhova, l6, korpus 4, kv. 31;Svetlana Evgeuievna Fedotova, Sojunzny prospekt, 26, korpus 1, kv. 58,both of Moscow; Grigory Moiseevich Bezverkhny, ulitsa Michurinskaya, 1,kv. 55, Leningrad; Sergei yikt qt IY $2! Olkhovskaya ulitsa, 17, kv. 23,

Moscow; Jury Palovich Deryabin,

ulitsa Kazansakaya, 4, kv. 67; Boris Iosifovich Sitnyakovsky, ulitsaFontanka, 134, kv. 5, both of Leningrad, all of USSR.

[111 3,747,281 [451 July 24,1973

[52] US. Cl. 51/204, 51/60 [51] Int. Cl 324d "/00 [58] Field of Search51/60, 156, 157,

51/204, 206, 206.4, 206 P, 206 NF, 211 H [56] References Cited UNITEDSTATES PATENTS 3,264,789 8/1966 Duesenberg 51/204 2,356,910 8/1944Bailey 51/211 H 2,347,246 4/1944 Barrett 51/211 H 2,275,339 3/1942Allison 51/206 NF 3,526,644 6/1966 Kistler 51/206 NF 3,074,211 l/1963Sacco 51/206 3,364,630 1/1968 Rusk 51/206 X 3,435,562 4/1969 Maillet...51/60 3,443,343 5/1969 Pratt...... 5l/206.4 3,465,480 9/1969 Hausermann51/157 FOREIGN PATENTS OR APPLICATIONS 1,451,464 7/1966 France 51/157Primary Examiner-Donald G. Kelly Att0meyWaters, Roditi, Schwartz &Nissen [5 7 ABSTRACT A cutting tool for forming articles which acquirein the process of machining the negative shape of said tool. The toolconsists of a holder and a shaped cutting element made of a compoundbased on polymers and cutting particles and fastened to said holder by ajoint which is capable of withstanding the load imposed by the forces ofcutting and of being easily destroyed during the replacement of thecutting element.

6 Claims, 9 Drawing Figures PATENIEDJULZMQH SNEEI 1 0f 3 PIE. 4

FIGJ.

PATENIEDJUWIQB 3. 747. 2a 1 SHEET 2 [1F 3 PAIENTEB JUL 24 I975 3 747,281

SHEET 3 OF 3 CUTTING TOOL FOR FORMING SHAPED ARTICLES The presentinvention relates to the field of material machining and morespecifically it relates to cutting tools for forming shaped articles andto the methods of manufacturing such tools.

Most effectively the present invention can be utilized in manufacturingcomplex-shaped graphite electrodes, designed for electroerosionmachining of dies and press moulds.

The currently known cutting tools for forming articles which acquire inthe course of machining the negative shape of these tools whichreciprocate in two relatively-perpendicular directions, said tools eachcomprising a holder with a shaped cutting element. The shaped cuttingelement of the known tools is made of metal and, as a rule, is integralwith theholder which is used for securing the tool in operation.

The cutting element of the tool has a shaped surface consisting of alarge number of cutting members standing out of the tool body. Thecutting elements can be formed either by means of manual serrations orby an electroerosion machining of the tool by a shaped electrode whichhas a positive shape of the product machined by the tool beingmanufactured. Both the first and second methods of making the knowncutting tools are labor-consuming, calling for a great amount of hardphysical labor (for serrating the cutting members or making the shapedelectrode) and professional skill. As a result of the manual work, theshaped surface of the cutting tool may deviate from the negative shapeof the product machined by this tool.

The design in which the shaped cutting element of the tool is madeintegral with the holder prevents (for reasons of economy) the use ofmaterials with high cutting properties for the manufacture of such atool, which adversely affects the tool strength. Therefore, the knowntools cannot be utilized for machining articles made of hard alloys andhardened steels. These tools are used for forming articles made ofgraphite, wood and other easily cut materials.

However, even in this case, the strength of the tool is not sufficientsince it loses its cutting ability after machining three to sevenarticles.

Experience has shown that it often becomes necessary to manufactureindividual complex-shaped articles in which case the use of said cuttingtools is not economical because the cutting portion of the tool and,consequently, its holder are used only once and their cost proves to behigher than the expenses involved in making the product directly,without this tool.

An object of the present invention resides in eliminating the aforesaiddisadvantages.

Another object of the present invention resides in providing a cuttingtool for forming shaped articles which, along with a simpler design andmanufacture compared with the known tools, features a highcuttingefficiency.

Another object of the present invention is to provide a cutting tool ofthe same type, which will ensure the manufacture of articles with a highaccuracy of machining which eliminates the need for the manual work of atemplet maker particularly in making dies and press moulds.

Still another important object of the present invention is to provide acutting tool of this type which will be cheap to manufacture andconvenient in operation.

In compliance with the above and other objects, in the cutting tool forforming shaped articles which acquire in the process of machining thenegative shape of said tool during its reciprocating motion in tworelatively-perpendicular directions, there are provided a holder with ashaped cutting element made of a polymeric compound and cuttingparticles secured to the holder by a joint which is capable ofwithstanding the load of the cutting force and is easily destroyedduring the replacement of said cutting element.

It is practicable that the shaped cutting element be secured to theholder by means of a binding layer of gypsum.

The most favorable solution of this problem is achieved when the tool ismanufactured by pouring a polymeric compound and cutting particles on apattern which has the positive shape of the article and, by removingsaid pattern after the polymers have hardened on its surface.

To impart high cutting properties to the tool, it is necessary, beforepouring in the compound, to cover the pattern with a layer of a stickymaterial whose thickness is less than that of the cutting particleswhich are subsequently applied to this layer.

Due to such a design and manufacturing method, the cutting tool featureshigh cutting properties and strength, ensures the manufacture ofarticles with a high machining accuracy, is cheap to manufacture andconvenient in operation.

Now the invention will be described in detail by way of example withreference to the accompanying drawings in which:

FIG. 1 is a longitudinal section of the cutting tool;

FIG. 2 is a longitudinal section of the cutting tool whose shapedcutting element is secured to the holder by means of a binding layer;

FIG. 3 is a longitudinal section through the pattern and the tool,showing their relative positions in the process of manufacture;

FIG. 4 shows the relative positions of the cutting tool holder andpattern before pouring in the binding layer (longitudinal section);

FIG. 5 is a perspective view of the cutting tool;

FIG. 6 is a perspective view of the pattern having the positive shape ofthe product, namely the rubber shoe bottom;

FIG. 7 shows a graphite electrode manufactured by the cutting tool anddesigned for the electroerosion machining of the press mould;

FIG. 8 shows a press mould for the manufacture of rubber shoe bottoms;and

FIG. 9 shows a finished shoe bottom.

The cutting tool for forming shaped articles comprises a holder 1(FIG. 1) and a shaped cutting element 2.

The cutting element 2 of the tool, according to the invention, is madeof a polymeric compound containint cutting particles and is fastened toa holder 1 by means of a joint which is capable of withstanding the loadof the cutting forces and of being easily destroyed during thereplacement of said cutting element. Such a joint may be constituted bya binding layer 3 (FIG. 2) of gypsum which fastens the cutting element 4to the holder 1. Shown in FIG. 1 is a tool whose cutting element 2 issecured to the holder 1 by the compound proper.

product, namely, the rubber Owing to such an arrangement the cuttingtool has an easily replaceable cutting element (2 and 4). Thus, theholder 1 can be used many times. Additionally, such a design of thecutting tool provides for making the shaped cutting element from apolymeric compound and cutting particles made of costly materialspossessing high cutting properties and strength, such as diamond, boroncarbide, etc., while the holder 1 can be made of conventional structuralsteel.

The shaped cutting element 2 of the tool, according to the invention, ismade as follows.

The polymeric compound (e.g. natural rubber, latex, coldor heat-curedplastics) and cutting particles (for example, artificial corundum orsilicon carbide) is prepared.

The size of the cutting particles is selected to suit the requirementsof the tool capacity and the surface finish of the articles machined bysaid tool.

For instance, for roughing work the size of the cutting particles rangesfrom 1 to 3 mm while for finishing operations it should be from 0.01 to0.03 mm.

The content of polymers in the compound varies from 20 to 60 percent ofits total weight. For example, if the compound consists of epoxy resin(molecular weight 360-470) with polyethylene polyamine as a hardeningagent, and cutting particles of electrocorundum, then the proportion is10 parts of epoxy resin, 15-22 parts of electrocorundum and 1 part ofpolyethylene polyamine.

The compound prepared in this way is poured on the pattern 5 (FIG. 3)into the space formed by the holder 1, said pattern having the positiveshape of the article.

The pattern is preliminarily installed on a plate 6.

It is practicable that the cutting properties of the tool be improved bycoating the surface of the pattern 5 before the application of thecompound with a uniform layer of a sticky material such as a consistentlubricant, for example fat-base grease. The thickness of this layershould be less than the size of the cutting particles which aresubsequently applied to this layer.

The inner surface of the holder 1 is degreased for better adhesion withsaid compound.

The holder 1 is secured relative to the pattern 5 by means of pins 7, 8,9 and 10. The compound is poured on the pattern 5 through the centralhole 11 in the holder 1. The pattern 5 is removed after the hardening ofthe polymer.

When the cutting element 4 (FIG. 2) is fastened to the holder 1 by meansof the binding layer 3 e.g., gypsum, the pattern 5 (FIG. 4) ispreferably coated with a layer 12 of a plastic material, for example rawrubber, plasticine, etc. before pouring in said binding layer.

The thickness of the layer 12 is equal to that of the shaped cuttingelement of the tool.

A core 13 placed on this layer 12 is used to form the gate spacerequired for pouring the compound on the pattern 5. Additionally, thelayer 12 has ribs 14.

Then the material of the binding layer 3 (FIG. 2) is poured into thespace formed by the holder 1 and layer 12. Then the layer 12 (FIG. 4) isremoved and the space formed between the binding layer 3 (FIG. 2) andpattern 5 is filled with the polymeric compound and cutting particlesfor producing the shaped cutting element 4 of the tool. The ribs 14protrude into layer 3 thus ensuring reliable adhesion of the cuttingelement 4 of the tool to the binding layer 3.

After hardening of the polymer, the pattern 5 is removed.

If the cutting tool is made with a complex-shaped cutting element whosesurface has thin protruding elements, it is practicable for theirstrengthening to install so-called needles 15 (FIG. 4) on the pattern 5;after pouring of the compound these needles remain in the body of thetool cutting element.

If the cutting element of the tool made of said compound is secured tothe holder by means of the same compound, it is practicable for reducingthe weight of the entire tool to make the holder with a possibility toremove its side walls after the filling in of the compound.

The working surface of the cutting element of .the tool may be made bysuccessive members. For this purpose individual members of the cuttingelement are assembled into blocks which are then fastened to the holder.

The tool forms the shaped articles as follows.

The cutting tool 16 (FIG. 5) made to the pattern 17 (FIG. 6) by themethod disclosed above is secured on a machine which imparts to saidtool a motion relative to the article 18 (FIG. 7), this motion beingsimultaneous in two relatively perpendicular directions X and Y (FIG.5), while in the third direction Z the article is fed to the tool 16perpendicular to the former two directions (X and Y). In this examplethe tool 16 has a holder 19 (with the side walls removed) with theshaped cutting element 20 fastened directly to it.

In the course of machining, the article 18 acquires the negative shapeof the cutting element 20 of said tool so that the hollows 21 (FIG. 5)and projections 22 of the tool correspond to the projections 23 (FIG. 7)and hollows 24 of the article 18.

In this particular case the machined article 18 is a graphite electrodewhich, in turn, is the tool for electroerosion machining of the pressmould 25 (FIG. 8) intended for moulding the article 26 (FIG. 9) i.e., arubber shoe bottom. The article 26 made in this manner is identical inshape and size to the pattern 17 (FIG. 6).

It should be noted that one and the same pattern can be used for makingtwo mating parts, such as the punch-and-die set of a blanking die.

In addition, it is to be noted that the tool can be used for finishing(grinding) the shaped working surfaces of dies, press-moulds and otherarticles of complex shape.

Thus, the cutting tool realized in accordance with this inventionfeatures broad technological possibilities and its use offers a hightechnical and economical effect.

Those skilled in the art will understand that the present invention canbe modified without departing from the spirit or the scope of theinvention since said invention is not confined to the versions shown inthe drawings and disclosed in the description, but is limited only bythe appended claims.

What is claimed is:

l. A cutting tool which is reciprocable in two perpendicular directionsto form an article which acquires the negative shape of the tool, saidtool comprising a hollow holder, a shaped cutting element carried bysaid holder and confined with-in the boundary thereof, said shapedcutting element being constituted of a polymeric material with cuttingmeans in the form of abrasive particles distributed in said polymericmaterial, and binder means filling said hollow holder between 4. A toolas claimed in claim 1 wherein said binder means is constituted of thesame polymeric material as the cutting element.

5. A tool as claimed in claim 1 wherein said holder is steel, and saidparticles are diamond, boron carbide, corundum, or silicon carbide.

6. A tool as claimed in claim 1 wherein said polymeric material is 20-60percent by weight of said cutting element.

2. A tool as claimed in claim 1 wherein said material of said bindermeans is gypsum.
 3. A tool as claimed in clAim 1 comprising needlesembedded in said cutting element and binder means.
 4. A tool as claimedin claim 1 wherein said binder means is constituted of the samepolymeric material as the cutting element.
 5. A tool as claimed in claim1 wherein said holder is steel, and said particles are diamond, boroncarbide, corundum, or silicon carbide.
 6. A tool as claimed in claim 1wherein said polymeric material is 20-60 percent by weight of saidcutting element.